linux-kernel - Re: [PATCH 2/2] clk: qcom: add IPQ9574 interconnect clocks support

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Date: Sat, 23 Mar 2024 01:29:00 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Varadarajan Narayanan <quic_varada@...cinc.com>, andersson@...nel.org,
 robh@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 mturquette@...libre.com, sboyd@...nel.org, djakov@...nel.org,
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
 linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] clk: qcom: add IPQ9574 interconnect clocks support

On 21.03.2024 05:31, Varadarajan Narayanan wrote:
> Unlike MSM platforms that manage NoC related clocks and scaling
> from RPM, IPQ SoCs dont involve RPM in managing NoC related
> clocks and there is no NoC scaling.
> 
> However, there is a requirement to enable some NoC interface
> clocks for accessing the peripheral controllers present on
> these NoCs.
> 
> Hence adding a minimalistic interconnect driver that can enable
> the relevant clocks. This is similar to msm8996-cbf's usage of
> icc-clk framework.
> 
> Signed-off-by: Varadarajan Narayanan <quic_varada@...cinc.com>
> ---

[...]

> @@ -9,9 +9,16 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
> +#if IS_ENABLED(CONFIG_INTERCONNECT)

This is bad practice, especially given the reasoning for your changes.

It's best if you add a dependency on interconnect to this driver,
otherwise things will go into uncountable EPROBE_DEFERs if there are
nodes consuming icc handles, but the supplier never registers.

[...]

>  
>  static int gcc_ipq9574_probe(struct platform_device *pdev)

.and that approach could save the probe func from the absolute mess it
has become with this patch

Konrad